The Top 10 Theories and Concepts in the Research Methods and Statistics Section of the EPPP

Often, preparing for Statistics on the EPPP is met with feelings of anxiety and can even be overwhelming. However, remember that this section is not heavily emphasized on the EPPP. Although it is helpful to take some time to learn concepts in this section, do not neglect more heavily emphasized areas on the EPPP. A good place to start with your review of Statistics is mastering these top 10 concepts and theories, allowing you a solid foundation for approaching the statistics material with greater confidence.

1. Types of variables

In getting started with statistics and research design, you need to first understand the differences between independent and dependent variables and be able to identify them in a sample study. Familiarize yourself with basic definitions. For example, when you think “dependent variable (DV),” be able to quickly remind yourself that the DV is what is being measured in a study. You will also want to know the difference between moderator and mediator variables.

2. Experimental and Quasi-Experimental Research

There are two main types of research that are performed: true experimental research (that uses random assignment) and quasi-experimental research that does not provide the researcher the same level of experimental control. Know the difference between random assignment and random selection.

3. Methods of Control in Experimental Research

There are several ways researchers attempt to control extraneous variables (a variable irrelevant to the researcher’s hypothesis but confounds the results in a systematic way). Be able to understand these methods, including random assignment, blocking, holding the extraneous variable constant, matching, and statistical control.

4. Internal and External Validity

What is internal and external validity and what are the threats to both? Be able to understand and identify when a study is experiencing one of these threats. As an example, you will want to know that pretest sensitization is a threat to external validity which occurs when the administration of a pretest sensitizes subjects to the purpose of the research study.

5. Experimental Research Designs

There are a few types of research designs which you will want to recall, including group designs, factorial designs, and the multiple types of single-subject designs (AS, Reversal ABA, Multiple baseline). One of the best ways to learn these various research designs is to create your own examples of studies that utilize each of these techniques. To best understand each of these research designs, it is helpful to understand why and when they should be utilized. For example, a reversal ABA design is helpful given that it allows for a return to baseline and better controlling for potential threats to the study’s internal validity.

6. Scales of Measurement

A popular test item on the EPPP assesses your knowledge of the 4 different scales of measurement: nominal, ordinal, interval, ratio. Develop an example of each scale of measurement as a means of learning the differences between them. An example of an ordinal scale of measurement is the Likert Scale. An example of a ratio scale could be number of calories consumed. Create your own examples and understand the characteristics of each.

7. Measures of Central Tendency

Another popular topic on the EPPP is central tendency and measures of central tendency. These include mean, median, and mode. Know and be able to recall their definition and use. Also, be able to understand which are most impacted when outliers in the data are present.

8. Statistical Hypotheses and Decision Outcomes

At the start of a study, researchers set to create a null and alternative hypothesis. These hypotheses are designed to determine whether or not the independent variable has an effect on the dependent variable. Understand when you can retain or reject the null hypothesis and Type 1 and Type 2 error.

9. Inferential Statistical Tests

Inferential statistics is often where test takers feel the most amount of anxiety. However, work to learn as much as you can and remember, statistics includes much more than this section. Focus on the material you feel you can adequately learn for the exam. Inferential statistics includes understanding the difference between parametric and nonparametric tests. Try to develop a basic understanding of the two as well as chi-square tests, t-tests, and ANOVAS.

10. Areas/Percentages Under a Normal Curve

The EPPP often will give one to two questions related to the normal curve and percentage cut off scores. Draw the normal curve including standard deviations and percentages. For example, you will want to be able to know that if M=50 and there is a standard deviation of 5, then 68% of people have scores between 45 and 55 (one standard deviation above and below the mean). Although this sounds complex, drawing out the normal curve on the whiteboard provided to you at the testing center will help to answer these questions.

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